There are three main penguin species in Antarctica (Chinstrap, Gentoo, Adelie). You can see them in the following figure:
Artwork by Allison Horst
Illustration of the three penguin species by Allison Horst
In this paper we want to answer the following questions
The data was collected on islands in Antarctica and published by Gorman et al. (2014). You can find the original paper with the title “Ecological sexual dimorphism and environmental variability within a community of Antarctic penguins (genus Pygoscelis)” in PLoS ONE1
The data is published via the palmerpenguins R package
which you can find on this
website.
The data contains (among others) the following measurements:
We did some plots, calculated some summary statistics and a linear model of the form \(y = ax + b\)
The mean weight of all penguin species is 4202. Gentoo penguins have an average weight of 5076 g, Adelie penguins of 3701 g and Chinstrap penguins of 3733 g.
The figure below shows that Gentoo penguins have the highest body mass.
ggplot(penguins, aes(x = body_mass_g, fill = species)) +
geom_histogram(alpha = 0.6) +
scale_fill_manual(values = c("darkorange", "purple", "cyan4")) +
theme_minimal()
Histogram of weight of the three penguin species.
There is a positive relationship between bill length and bill depth for all 3 species, as the figure below shows.
scatter <- ggplot(
data = penguins,
aes(
x = bill_length_mm,
y = bill_depth_mm,
color = species,
shape = species
)
) +
geom_point(size = 3, alpha = 0.8) +
geom_smooth(method = "lm", se = FALSE) +
scale_color_manual(values = c("darkorange", "purple", "cyan4")) +
theme_minimal()
plotly::ggplotly(scatter)
Scatter plot with regression lines showing the relationship between bill length and bill depth for the 3 penguin species
In general, it looks like the body characteristics differ between the sexes but also between the penguin species, as the table below illustrates:
## # A tibble: 6 × 6
## # Groups: species [3]
## species sex bill_length bill_depth flipper_length body_mass
## <fct> <fct> <dbl> <dbl> <dbl> <dbl>
## 1 Adelie female 37.3 17.6 188. 3369.
## 2 Adelie male 40.4 19.1 192. 4043.
## 3 Chinstrap female 46.6 17.6 192. 3527.
## 4 Chinstrap male 51.1 19.3 200. 3939.
## 5 Gentoo female 45.6 14.2 213. 4680.
## 6 Gentoo male 49.5 15.7 222. 5485.